Lipo Chargers or How Not to Burn Down the Makerspace

Aerospace / RC
#1

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I was charging one of my small 130mah batteries for my nano quad, I guess I didn’t pay attention to the current setting and watch it closely and it caught fire/exploded. Luckily the fire went out before I got the fire extinguisher (which wouldn’t help an electrical fire) but it made a nasty burn on the table and burnt the charger.

I do take full responsibility for the damaged charger, it still seems to work except the LCD and buttons are charred. I can replace it with a new one I don’t know who the owner is though. @hasbridge suggested we make a lipo battery bunker and put up a warning sign to watch your batteries (Ironically, theres a giant red sticker on the charger warning me of exactly what I didn’t do) and we should have a sign on proper use of the chargers.

I’m going to stick to my small 300mah USB charger for now, I don’t want to make that mistake again.

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#2

I have never seen them here, but some hobby shops in AZ, NV or CA sell a ceramic urn or a heavy plastic pouch to contain the battery pack under charge.

Maybe go back to the Foundry and make one?

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#3

I’m glad no-one was hurt… Thanks for being excellent by reporting the issue, and sending a powerful reminder to everyone to use caution (and Know how to use the tools…)!

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#4

The safest solution would be to build a battery bunker for charging batteries in. The easiest way is to get a concrete paver, and put a cinder block on it with the holes facing up. If a fire does happen, it will contain it and keep it from spreading. Unless there are any objections, I’m more than happy to build one. Also, we should probably have a rule that states something like “No charging lithium batteries unattended”.

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#5

I am absolutely no expert on LiPo batteries, but I agree with you they should be charged on something that can resist high temp. Was curious and did some quick research at battery manufactures, more concerned about what toxic fumes are produced and their suggestions for extinguishing … well controlling would seem to be a better word, LiPo fires.

FWIW I did see this product Large Lipo Battery Charging Bag that only $15 and may be something the Space wants to buy a couple of as safety equipment, these could be used inside your cinder blocks to further control flame/explosions.

It would also seem that a container of one several dry materials could be near the charging station to help smother the flames according the manufacturers’ MSDS sheets. Typical example in MSDS:
Energizer Battery
SECTION III - FIRE AND EXPLOSION HAZARD DATA
If fire or explosion occurs when batteries are on charge, shut off power to charger.
In case of fire where lithium polymer batteries are present, flood the area with water. If any batteries are burning, water may not extinguish them, but will cool the adjacent batteries and control the spread of fire. CO2, dry chemical, and foam extinguishers are preferred for small fires, but also may not extinguish burning lithium polymer batteries. Burning batteries will burn themselves out. Virtually all fires involving lithium polymer batteries can be controlled with water. When water is used, however, hydrogen gas may be evolved which can form an explosive mixture with air. LITH-X (powdered graphite) or copper powder fire extinguishers, sand, dry ground dolomite or soda ash may also be used. These materials act as smothering agents. (emphasis added)
Fire fighters should wear self-contained breathing apparatus. Burning lithium polymer batteries can produce toxic fumes including HF, oxides of carbon, aluminum, lithium, copper, and cobalt. Volatile phosphorus pentafluoride may form at a temperature above 230F

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#6

For future charging… Make a box or container made of cement board (1/4" thick). Much lighter and smaller than a cinder block, but still non-flammable and non-combustible. It will be more mobile and look more stylish.

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Another concern is the ratings of the fire extinguishers… What class are they? There are electrical machinery as well as lasers and chemicals. Shouldn’t you have the appropriate safety equipment in the building.

As @Photomancer mentioned the MSDS mentions having some sand or related material as a smothering agent. Might be a nice thing to have in the shops area as a backup.

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#7

Agreed!

Also, thanks to everyone posting potential solutions, and volunteering to make the solutions happen!

Perhaps one or more of our Board members may have some discretionary funds available to help purchase materials to build out a safer charging area, and supply an appropriate extinguisher to have within arm’s reach…

#8

So @Brandon_Green uses lipo charging bags like this: http://www.amazon.com/gp/aw/d/B005Q3U7BS/ref=mp_s_a_1_4?qid=1443924351&sr=8-4&pi=AC_SX110_SY165_QL70&keywords=lipo+bag&dpPl=1&dpID=31QXMhyBvpL&ref=plSrch

Unless anyone has objections, he’ll order a couple for the space later tonight

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#9

I charge my lipos in bags like that, and also keep my batteries in them when I fly somewhere.

#10

@photomancer Lipo bags will help, but they are not sufficient in my opinion. They can contain a very small lipo, but if a 4 cell 5000mah decides to go up a lipo bag doesn’t stand a chance

#11

The gray version provided additional fuel for the fire…

Sitting on top inside of a cinder block seems like a better choice…

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#12

Just threw that out as a suggestion I saw when looking up toxic fumes & LiPo fires after seeing charred remains of another member’s battery pack, I will defer to your experience as mine are limited to camera/computer batteries which typically don’t have speed demon recharge modes. Merissa recommended a larger bag and Lisa suggested that the Space buy two thus supporting you view. Abel Ramirez & Bill showed other strategies in addition to your block strategy (which based on the last video posted looks to be simple and effective. While the bag may not contain an intense fire of multiple batteries, it will help contain/dampen any that explode. Considering how often I see these often being recharged on tables in the Commons Area containment for even short interval is probably a good thing.

It looks like you all have a solution at hand.
But if a large battery has the potential you are implying then maybe recharging those in an area people like the Common’s congregate should be reconsidered or at least fast recharges inside (my meager understanding is rapid recharges are more likely to overheat-catch fire or explode). The fact these fires are hard to suppress is another concern - similar to magnesium part fires in machines centers.

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#13

That is correct charging at more than 1c is generally considered hazardous. 1c refers to a batteries capacity relative to charging rate. Ex. 1000mah battery charged at 1amp =1c 1000@ 2amps= 2c.

Another danger is older puffy batteries. Lipos become puffy with use over time. They can be more dangerous.

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#14

I was at the space yesterday and realized where the ‘event’ happened. After seeing some YouTube videos of properly contained charging failures and all the smoke that is created… I know I wouldn’t chance charging these indoors.

I guess I expected this event happened in the shop area with high ceilings and some ventilation.

#15

That video sure makes me concerned about using a lithium charging bag. The cinder block idea seems cheaper and easier. It would be very messy to have a bag of sand inside though. We should move battery charging somewhere in the warehouse or outside maybe. I know a lot of the R/C car guys bring their own chargers.

#16

The LiPo bag I think is lieu of a more formidable containment system.

The advantage of the sand bag system is in its simplicity. Made of heavy duty plastic sheeting and permanently sealed shut it wouldn’t rip under normal handling. If a fire occurs, the mess would be welcomed having helped suppressed fire/smoke/gases while eliminating the need keep a container of material nearby.

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#17

Here is the best solution for this particular situation. The Venom Stronghold DC LiPO Balance Charger has a built-in fireproof box to contain the battery while it’s getting charged.

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#18

That is a pricey model and still requires a 12V+ power supply.

#19

I plan on bringing some cinder blocks, cement board, and a bucket of sand next weekend to make a cheap battery bunker out of. The sand bucket can just sit under the table, and in the event of a fire (inside the bunker) we simply dump the sand in to smother it.

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#20

I believe you also want to be wary of batteries that have experienced physical shocks. I’ve understood for example that after batteries have had a hard model airplane crash, that they can sometimes burst into flames minutes or even hours after the incident. In that way, caution is advised for storage, and not simply during a charging cycle.

Additionally, you’ll probably want to be wary of temperature. Some of these containment bunkers, when combined with high charging or discharging rates, could lead to elevated battery temperatures. I’ve understood that in the best case, high temperatures will shorten the life of a cell. And in the worst case, it will significantly increase the chance of fire. Therefore, it’s worth thinking about airflow or some mechanism to keep temperatures reasonable.

FWIW - from what I’ve seen, the only reason we can trust phones and laptops so much these days, is that those products have very detailed energy management and protection circuits, with lots of safety systems - over-voltage, under-voltage, over-current, cell temperature, cumulative-mAH-counts per cell or pack, etc… In contrast, so many battery packs for R/C systems seem to be simply raw cells, often without any built-in protection circuits… I’m not suggesting to avoid LiPo. But I am suggesting that you can’t treat them like Alkaline or NiCd -> LiPo deserve a special respect…